Is this 964 C4 deal worth considering? (w/ pics)

[black_falcon]

Looking at a 1991 C4 with 113k. Same owner since 1995, service history from new. Recent work (last ten years) includes oil return tubes, pressure regulator with intake seals, timing cover gaskets, distributor caps and plugs, fuel filter, intake Plenum, valve cover gaskets at 91k, new clutch in 1997 @ 69k, and lots of misc. small stuff. Motor has never been opened.

Aesthetically the car looks near showroom new inside and out.

What worries me:

- Vast array of warning lights: "!"with the interlock and brake warning lights, pad wear light (needs rear pads) and the check engine light haphazardly comes on and off with no real pattern. I believe there was another on (airbag?) near the speedo.
- Last valve adjustment was around 75k, and on the invoice it says "Cylinder leakdown 23% all cylinders" which seems high?
- An invoice from 100k indicates the valve covers leak and rear CV boots have slight leaks.
- AC Inop(Resistor)
- Service history tapers off around 2008.


The car runs and drives nice, and is tempting for $15k. Looking for your thoughts...

[scottrx7tt]

i would be worried about the 23% leakdown test myself. you should atleast test the compression, and leakdown again.. i bet it was tested at 2-3% leakdown.

[Justin@Athens]

I would get PPI somewhere you trust. Have the owner pay for a valve adjustment, and then do another leakdown. I am also betting 2-3% is what was supposed to be recorded. With that said, I think this car is a great buy at 15k with only some deferred maintenance to catch up on.

[Kidasters]

I'd be wary. 23% leakdown means the engine needs to be rebuilt.

The interlock light is probably one of the lateral accelerometers. In my 964, one of them was bad. I was able to milk it for awhile by taking it out and cleaning the contacts (they are located in the front of the tunnel), but it died. Porsche no longer makes them. Only people that sell them are LA Porsche dismantler, and they are $800 or so per (and there are 2).

Check engine is probably O2 sensor - or it's an intake leak. If the 23% leakdown is right, it's because the engine is shot. If not - it could be boots on the intake leaking, causing a knock sensor to fire. Easy to repair, but you have to remove the entire intake to do it.

Overall - it needs work. Minimum of about $2000 of work (brakes and accelerometer). If it needs a new engine, good grief - you are looking at a lot more - maybe 8-10 K. On a car that, at most, is worth about 20.

I think at 15 it's not a deal. At 10, maybe.

Good luck. I like the 964. I really miss mine. Classic 911 lines, but the 4wd, power steering and ABS were nice.

[jplucas]

It's a terrible deal. Please send me their contact info so I can tell them so.

[black_falcon]

Typo, leakdown was 24%, not 23% (same thing, I know) and that was back in 1998 at 75,000 miles.

The motor pulls reasonable well, similar to other 964's I have driven. I would think an obvious performance loss/running issues would be noticed with such a large number?

Thanks for the replies so far.

[mca]

Pay for a PPI. I seriously doubt that all 6 cylinders had the exact same leakdown. I bet it wasn't done correctly.

If engine checks out, I'd be all over that for 15k (if it was a C2).

[r-mm]

I had a PPI done on a 135k mile C4 and got leakdown numbers all over, several in the 10's and 20's. I offered $10k (asking was $17k) to account for a top end rebuild, offer was not accepted, did not shed a tear, looking for a 3.2 now.

As with dynos, leak down gauges vary so the most meaningful numbers will be from a PPI you commission from an experienced shop who can tell you what the numbers mean and put them in context.

The idiot lights and what they portend are basically why I stopped looking at 964s. I love everything about them but the liability that comes from owning a more complex car.